Winter as we know it is on "borrowed time," according to a national environmental group that on Thursday said climate change has cost the ski resort industry $1 billion over the past decade.

The report by the Natural Resources Defense Council and the nonprofit group Protect Our Winters comes after a frustratingly dry winter of 2011-12.

Ski runs were mostly bare earth until mid-January. Desperate to attract business, one Sierra resort held a "Pray for Snow" gear sale in late December, while another hosted a "beach party" barbecue well after the New Year.

These extremely dry winters are more likely in the future, the groups say.

"Last year we had a front-row seat on what climate change could look like in states dependent on winter tourism," said Chris Steinkamp, director of the Pacific Palisades-based Protect Our Winters. "This is really serious business to all of us."

Steinkamp said the groups published the report to put a dollar sign on the impact of climate change on winter sports - an impact that until now has been described mostly in anecdotal terms.

In California, low-snowfall winters over the past decade have cost the state nearly $100 million and 1,200 jobs compared to higher-snowfall winters, the report finds.

The consequences of last winter's lousy snowpack were evident at Bear Valley Mountain ski resort. Year-round employees were laid off in June, casting doubt over whether the resort would operate at all this winter.

Officials announced in October that the resort would, indeed, open. That opening is scheduled for Dec. 21.

"This industry, I would say, needs to take its head out of the snow before it melts away, and look at the hard realities of what climate change holds for them in the future," said Antonia Herzog, assistant director for climate and clean air with the Natural Resources Defense Council.

The industry took its head out of the snow many years ago, said Bob Roberts, a spokesman for the California Ski Industry Association.

Resorts are well aware of climate change and have not only tried to decrease their own carbon footprints but have also advocated for legislative efforts like Assembly Bill 32, California's landmark greenhouse gas reductions measure approved in 2006.

"We've been engaged with this issue, we're aware of this issue, and we're taking it in stride," Hunter said. "But we don't look at this as Armageddon."

Many resorts have ramped up summertime activities to create year-round revenue, rather than relying solely on winter income, he said.

"It's not as if our industry is asleep at the switch," he said. "It's not."

A Bear Valley marketing official did not respond to requests for comment.

Half of the nation's ski resorts last year were late to open and early to close, Thursday's report says. Others resorted to using expensive snow-making machines.

Nationwide, the ski industry lost $1 billion in low-snow years over the past decade, as well as somewhere between 13,000 and 27,000 jobs (6 to 13 percent of the industry total).

Last month, a separate study by Stanford Woods Institute fellow Noah Diffenbaugh found that the snowpack could shrink significantly over the next 30 years in key parts of the Northern Hemisphere, with the Western U.S. seeing the biggest jump in extremely low-snow years.